Hoisting apparatus



Nov. 27, 1951 D. A. WALLACE 2,576,158

HOISTING APPARATUS Filed Nov. 22, 1946 4 Sheets-Sheet 1 HTTORNL'K Nov. 27, 1951 D. A. WALLACE HOISTING APPARATUS 4 Sheets-Shet 2 Filed Nov. 22 1946 /7 T'TORNEK 1951 D. A. WALLACE 2,576,158

I-ICISTING APPARATUS Filed Nov. 22, 1946 4 Sheets-Sheet 3 HTTORNE'X Nov. 27, 1951 D. A. WALLACE HOISTJNG APPARATUS 4 Sheets-Sheet 4 Filed Nov. 22, 1946 a. u w

INV EN TOR. pa vza? A? lo allqcz. B

)ZTTbRA/Er Patented Nov. 27, 1951 David A, Wallace, Grosse Pointe, Mien, as'sifi'i'ioi to Walco, Inc., Detroit, Mich., a corporation of Michigan Application November 22, 1946, Serial No. 711,649

"23 Claims.

This invention relates to improved hoisting apparatus of the class disclosed in my copending application Serial No. 653,386 filed March 9, 1946.

The hoisting apparatus shown in the above mentioned "application includes an extensible boom member mounted at one end for pivotal movement from a Substantially horizontal to a substantially upright position by fluid pressure operated mechanism. The boom member inthat unit com-prises a single extensible piston and cylinder assembly, which in contracted -position is vertically aligned with one of the elements of the fluid pressure operated mechanism and of sufficient 'cross "sectional dimensions to independently sustain its intended load.

One of the main objects of this invention is to provide in a hoisting apparatus of this kind a pivotally mounted boom member havinga pair of laterally spaced extensible piston and cylinder assemblies each being of materially less cross sectional dimensions than that required of a single assembly of this kind, and between which portions of a fluid pressure operating mechanism nest horizontally in order to greatly reduce the depth of space required to accommodate the hoisting apparatus in contracted state.

;A further object of the invention is to provide in a boom member of hoisting apparatus of this character a pair of laterally spaced and rigidly connected extensible piston and cylinder members which effectively stabilize the boom member against lateral beam-like deflection and lateral wabble with respect to its pivotal axis Another object of the invention is the provision of a pair of laterally spaced horizontally aligned piston and cylinder assemblies in the fluid pressure mechanism for rotating the boom member whichare accommodated in a space of relatively small vertical height.

One of the most important objects of the invention is to provide a hoist of this character which may be collapsed into a space of relatively small total height without sacrificing theultimate lifting power and stability of the hoist.

A further object of the invention is to provide a pivotally mounted load receiving seat on a rotatable and extensible hoist boom member of this character which is frictionally restrained against pivotal movement from an intended load receiving position but pivotally movable against such frictional restraining action in order to efiectively and securely sustain a load in its various positions of arcuate movement by rotation of the boom member from a substantially 'hofi' zontal to a. substantially 'iipi ight position and vice-versa. I I n 7 Another object of the -irii ention is "to provi e pivotally collapsible supporting legs in a load receiving seat of this character-which are rfiovable into non-protruding positions when the ho'ist is not in use? Another object of thefinjfhtion is to provide a load receiving seat of this character which is mainly receivable in {a space which is longitudinally aligned with the boom member and its operating mechanism when the latter is in its horizontal position. n

Another object of the "intention is to provide in the fluid pressure ope'rated 'nffecliani'sm by which the boom member is rotated "about its pivotal axis shif-table toggle 'fn'ean's and ias'so elated "guide track which coast to limit rbrau vp movement of the 'boom member to "an upright position slightly inclined with respe'ot' t'o a 'vertical plane -in order to assure an oppbsaeiotauve movement eofthe boom member under it's own weight when desired, or under its weight and the load sustained by it. k H J Other objects thein vention are to "provide an improved guide track and wheel assembly for the toggle means, todprovide a track which has inwardly facing channel rail mernbers provided with converging channel walls with which tapered peripherallportions of a pair :of Wheels are engageable, andto provide flanges on the peripheries of such wheels which \efiectively limit inward insertion of the Wheels into the channels of the rail members in order to preserve the pertions of the channels adjacent the webs of the rails 'for the-accommodation of fluid pressure lines.

An additional object of the invention is the provision of a pressurersensitive valve mechanism which accommodates aara'pid inlet :of fluid pressure rrn'ediu'm into the boom elevating and extending icylinders 'of the power actuating mechathem and which limits the rate of flow of -fluid pressure medium from suchcylinders.

Other objects of the invention are to provide simplified'self engaging latch mechanism -for releasably holding the boom -member against unintended rotation from an upright toward its horizontal position, and to provide improved latch mechanism :for ;holdingfthe pistons "of the boom member against extension relative to the cylinders thereof when the bo'dmrnember is in its lowered position. W n

An additional 'object of the invention is to pre- 3 vide an improved cover for the space in which the hoisting apparatus is accommodated whennot inuse and improved means for shifting such covers to uncover said apparatus as it lifts a vehicle or other object.

An ilustrative embodiment of the invention is shown in the accompanying drawings in which:

Fig. 1 is a side elevational view, partly in perspective and partly in section illustrating the improved hoisting apparatus as applied to the lifting of a motor vehicle.

Fig. of the pair of units shown in Fig. 1, showing the unit in its contracted position.

Fig. 3 is a longitudinal sectional'view taken on line 3-3 of Fig. 2, illustrating the elevated and intermediate positions of the hoisting apparatus in dot and dash lines.

Fig. 4 is a vertical sectional view taken on the line 4-4 of Fig. 7 3.

Fig. 5 is afragmentary sectional view of the valve mechanism included within the dotted circle indicated by the letter C in Fig. 2.

, Fig. 6 is a transverse sectional view taken on the line 6 -6 of Fig. 2.

Fig. '7 is a transverse sectional view taken on the line 1-1 of Fig. 2.

Fig. 8 is a fragmentary horizontal sectionalview taken on the line 88 of Fig. 3.

Fig. 9 is a fragmentary longitudinal vertical sectional view taken on line 9-9 of Fig. 2.

Fig. 10 is a plan View of the fluid pressure and control system shown in perspective in Fig. 1.

The improved hoisting apparatus shown in the drawing may be mounted on the floor of a building or other floor-like structure but it is preferably disposed in a-recess ll) of a floor structure or in a corresponding recess of a platform laid upon a floor structure as disclosed in my co-pending application Serial No. 653,386. A pair of laterally spaced'longitudinally extending channel rails I! are mounted in the recess with their channel sides facing each other. Each rail ll includes a vertical web portion 12 and spaced horizontal flanges 13. The flanges 13 are provided with converging surfaces l4 on their inner sides.

The apparatus shown in Fig. 1 includes a pair of substantially identical hoisting units A and B, the description of one of which will serve for both. While two hoisting units are preferably employed in hoisting avehicle, only one may be emplyed for lifting the ends of a vehicle one at a time.- Any desired number of hoisting units may be used as require by the nature of the object or load to be lifted.

Each hoisting unit A and B, comprises a base or carriage generally designated by the numeral 15 having a yoke shaped member I'B extending transversally between the rails and provided with spaced arm portions ll on which axles [8 are mounted. The opposite end portions of the axles I8 project beyond the sides of the arms [1 providing inner and outer trunnions l9 and 20. Journaled on the outer trunnion of each axle I8 is a wheel 2| having a tapered periphery 22 disposed between the converging inner side surfaces 14 of the rails H. A flange 23 is provided on each wheel 2| for engaging the outer edges of the flanges 13 to prevent insertion of the wheels beyond a spaced location from each Web l2 of each rail in order to accommodate cer 'tain conduits hereinafter referred to, between the flange and outer side of the wheel.

A boom member, generally designated by the 2 is a plan View of one hoisting unit,

numeral 24, is pivotally mounted at one end on the carriage l5 for rotation about a substantially horizontal axis. The boom member 24 includes a pair of piston and cylinder assemblies each having a cylinder member 25 and a piston member 26 disposed in telescoping relation. Each piston member 26 has a piston head portion 21 adapted to operate in sealed relationship with its respective cylinder 25. The right end of each cylinder 25 is closed by a cap structure 28 having a projecting web portion 29 provided with an aperture 30 in which a bearing 3i is disposed. Each cylinder 25 is journaled on a trunnion portion 20 of each axle I8, respectively, the trunnion portion 39 of each axle being received in the bearing 3i of one of the webs 23.

The cylinders 25 of the boom member are rigidly connected together and held in spaced relationship by upper and lower transverse metal cleats 32 and 33 which are welded or otherwise suitably secured to the cylinders 25. An intermediate transversally extending metal cleat 34, shown in Fig. 7, also aids in rigidly connecting and spacing the cylinders 25. This cleat 34 is welded to the cylinders 25 and is provided with outwardly extending trunnions 35 which project beyond the cylinders 25. Each of the cleats 32, 33 and 34 have a flat side disposed in a common plane on the right side of the boom structure,

as viewed in Fig. 3, on which is mounted a cover plate 36 that is of sufficient width to cover the recess iii in which the hoisting apparatus is disposed and it is of sufiicient length to cover that portion of the recess ID in which the main length of the boom member 24 is accommodated when the apparatus is in its contracted state. The plate 36 may be secured to the cleats 32, 33 and 34 by screws 3'! or otherwise fixed thereto in order to serve as a rigidifying and re-enforcing element of the boom member.

The outer ends of the piston members 26 are connected together by a transversally extending bar 33 having outwardly extending flanges 39 projecting from the side of the bar 38 remote from the piston members 26. The flanges 39 are provided with registering apertures 43 in which are received pins 4| which pivotally support a load receiving seat generally designated by the numeral 42 which is adapted to engage and support one end of a vehicle. The seat 42,

' shown in Fig. 4, is particularly adapted to engage with the rear axle of a vehicle and would be provided on the hoisting unit designated B in Fig. 1. The hoisting unit A of Fig. 1, may be provided with a similar seat structure or it may be varied as desired to receive a predetermined portion of the front end of the vehicle. The load receiving seat shown somewhat in detail in Fig. 4, includes a horizontal bar 43 of channel shaped cross section having spaced pairs of flanges 44 projecting from its web between which the flanges 39 of the bar 38 are received. The flanges 44 of the bar 43 are provided with registering apertures for receiving the pins 4| by which the load receiving seat is pivotally mounted on the outer ends of the piston members of the piston and cylinder assemblies. Waved washers 45, or other suitable friction means are interposed between the flanges 39 of the bar 38 and the flanges 44 of the bar 43 to frictionally, yieldably oppose pivotal movement of the seat 42 relative to the piston members of the boom member. Pivotally mounted at 46 on each end of the bar 43 is a support 41 which is also preferably of channel shaped cross section. The web mfsT ow'ard its upright position is produced by toggle comprising a pair or links 55 each jotii'naled at one en on one or the trunnid'ns 55'. The" opposite ends of th links 55 are journaled oh axles ofa earn V the numeral 52 which has a central frame; s'tru'c tfiie 53" on which the ashes 5| alf'e mounted;

Whel's 54 are joui'halfed on the a'gles 51 and engaged between the anges s or the rams n. The" Wheels 54 are idfitic'al cbl'lstruction to the wheels 2| or the carriage t5 and therefore r'duii no further ds'cripti'c'in'. b

The carriage 52 1s adapted to be shifted rightto rotate the boom membe toward its upper position by a pair of piston and cylinder assembl'ies, generally d'esigiiated by th'enunier'al 5'5, each of which includes a cyliridr"56 having a pistenjl, shown on Fig. 9,.threifi. Each piston 5 't isprovidedwith a piston rod 58 which isrigidly fined at its outer end to the frame mefnber 53 o f the carriage 52, Eightward movement of the pistons; 51 and piston rods 58 urges the carriage 52;. toward; the pivoted hu 6f. the bdon'i 24 thereby causing the links 50 to rotate the boom member toward its upright position. The pivotal a gi -sot the right end of each link 50' is located slightly above the elevation of the pivotal axis of the left end of each linkwhen the boom member is in itshorizontal position in order" to assure the intended rotation of the boom member when the carriage 52 is urged rightwardly. A pin 59' extends outwardly from each link 55 into the channel of an adjacent rail and engagesthe upper' flange I3 thereof to limit rotation of the boom member to a position slightly off vertical I ,Jeurnaled on one or both of the axles I8 of thecarriage I5 is a latch element 60 which is adapted to engage with a pin 6} which protrudes outwardly from the link SQ. Qlockwis rotation of; the latch element 60 islimited by a pin 62 on the frame 16 of the carriage l5 and whe n the boom member is in its upright position, counterclockwise rotation of the latch 60 is limited by a chain 63 connectedtd the latch element and the cylinder 25. As the boom member approaches its limiting upright position the pinfil on one or the links engages the surface of the latch element 60 and rides upon such surface until the pin is seated; in the notch 65 of the latch element 60L The latch element positively holds the boom structure against unintended countercloeliwise rotation and maybe manually released when it is desired to lower the boom member. VJ

A latch element 66' pivotally mounted at 6"! on oneof the cylinders 25 is adapted to engage with ap latch pin 68 extending outwardly from the bar 38' which connects the outer ends of the piston members 26 in order to releasably hold t he piston members against unintended outward extension when the boom member 24; is in its horizontal position.- Ihelatch 66 is preferablyprovided with a weight 69 at itsfree end and the pivot is sat dqu rtisala sn e w h th P n 5.3 when the boom member is in its upright position ded' with a notchl8 Fig. 3 order to facilitate rotatio or ard its horizontal position g'e' generally designated a ains 56* that; the area el comes disengaged fromthe pin by gravity actiorr When theboorrl member 24 s its upright 1555i:

tioii' the main portion of the space withinithe recess ['0' fro which it' was rotatediscovered a; plate 11 which is mquhted at its-right en af supp ort' l2 carriedby the carriage 52R. other end of the plate 1:- is beveled s; at 12' sh as tb' ride up over the left the oftheirecesis It} as the plate "H is Shifted leftwardly by leftward movement of the carriage 52 which occurs dur ing counterclockwise rotation of the" boom' meet:

her 24. In the case of the unit B the cover'plait' ll thereof is also beveled at its left extremity" in order to ride up over and slide upon a'cover plate 13 which is disposed over the p'o'rtion' or the recess in which the cylinders 56" of the boom rotat ihg' mechanism are accommodated.

Moun'ted on the outer sides of each of the cylinders 56 of the unit A areftsjlhel supporting hr'ackets 14 on which wheels 15 are jhmhhee. Thewheels 15 are identical to the whee1s2l and Stand they are likewise received between the ee e's I3 of the was 1:, wheels" 15- may be provided on the cylinders 56' of hoisting ufiit B if itis desired to permit shifting 6f bdth Hoistifig units.

However hoisting unit B may be fixed against shifting 011 the h irs ll Whil hoisting iiiiit A permitted to Shift in OIdef t6 acbrhihfidlt apparatus to vehicles of different wheeihases. It should he noted that as the Boom members of theapparatus are rotated toward their horizontal positions the C'Ov'l" plates 'H aie shifted mil) Of the way and the spaces previously covered thereby ali' coverd by the plates 36 when the boom menihers reach their horizontal positidhs. It will be seen in Figs. 3 and 9 that the load suppc'irting seat 2' fits into the space between the wheel's 54 6f the carriage and the left ends of the pistons 26 cylinders 25 of the boom member. Substantially" the entire boom structure is nested in the riecess I0 and the piston rods 58 of the cylinders stare nested between the cylinders 25 of the boom member 24. Only the supports 41 of the load receliying seat extend substantially above the level of the open side of the recess II] when thehoisting apparatus is contracted. By employing a pair of piston and cylinder assemblies in the boom memher and a pair of piston and cylinder assemblies for rotating the boom member the overall con; tractd height of the apparatus is greatly reduced wit out sacrificing strength or load capacity; Nesting of the various parts together as above set forth, when the apparatus is contracted further reduces the depth of space required for its acconimbdatioh.

b Fig. 5 of the drawings is illustrated an proved valve member for producing a differential between the rate of ilow of fluid pressure medium into the cylihders 56 and 25 and the rate of new fluid pressure medium from the latter. This val e mechanism permits rapid fillingbf the respecfl' cylinders but meters thefiow of fiiiitl ihdiinn therefrom seas to'sliiw down the rate of longitudinal contraction of the boom member as well as the rate of its rotative movement from' an uprightto a horizontal position. The difierterior of the cylinders 58 on the left sides of the" pistons 51. Communication between the 'conduits'83 and the interior of each cylinder 58 is established bya passage 84 formed in an end seal 85 which is provided in the left'end of each cylinder 58 as illustrated in Fig.9. The valve casing 82 has an opening 88 intermediate its ends in which is threaded a sleeve 81. The outer end of the sleeve 8'! is connected to a conduit 88 by' which fluid medium under pressure is supplied from the source hereinafter described. Axially slidably' mounted inthe sleeve 81 is a tubular valve element 89 having an open end facing the conduit 88 and an enlarged closed end or valve head 98 disposed externally of the sleeve 8'! and provided with a metering orifice ill. The head 98 of the valve element. is adapted to seat upon the inner extremity of the sleeve 87 so as to effectively close the inner end of the sleeve when thevalve element is in the position shown in Fig. 5. The valve element 89 is held against axial displacement from the sleeve 81 by a pin 92 mounted on the wall of the sleeve and extending into a slot 93 formed in the tubular part of the valve element 89.

When fluid under pressure flows into the casing 82 from the conduit 88 the force of the fluid shifts the valve element 89 leftwardly, as viewed in Fig. 5, so as to uncover a plurality of ports 94 in the valve element in order to allow a relatively free flow of fluid simultaneously through the ports 94 and through the metering orifice 9|. During reverse flow of fluid from the interior of the easing into the conduit 88 the valve element 89 is shifted rightwardly from its extended position to the position shown in Fig. 5, in which the metering orifice 9I provides the only path for fluid flow to the conduit 88.

The hoisting apparatus may be supplied with fluid pressure from any desired source and under the control of any suitable valve mechanism such as that shown in my co-pending application Serial No. 653,386, or in Figs. 1 and 10 of the drawings. In Figs. 1 and 10 of the drawings there is illustrated a reservoir or tank 95 on the top of which is mounted a motor 98 which is drivingly connected by a shaft 91 to a pair of pumps 98 and 99. The pump 98 draws fluid from the tank 95 through a pipe I88 and the pump 99 draws fluid from the tank through av pipe IN;

The outlet of the pump 98 is connected by a pipe I82'to a relief valve I83 which has a normal outlet connected to a conduit I84. The relief valve I83 has a valve controlled outlet communicating with a pipe I85 through which fluid medium is returned to the tank 95 when the pressure created by the pump 98 exceeds a predetermined valve sufliciently to open a valve element I88. Fluid pressure medium is conducted by the conduit I84 to a check valve I81 having a valve element I88 which -opens rightwardly, as viewed in Fig. 10, under the pressure of fluid medium in the conduit [84. The check valve I81 is connected to a conduit I89 which leads to a manual control valve H8. The conduit 88 which serves the cylinders 58 of one of the hoisting units A and B is connected to the other side of the manual control valve H8. I

A conduit III leading from the inlet of the differential valve 8| which is associated with the cylinders 25 of the boom member is connected through a manual control valve I I2 with the con duit I89 at a location between the check valve I81 and the manual control valve II8. An ex haust line comprising a conduit H3 is connected to the conduit I I I on the side of the manual con-' trol valve II2 remote from its connection with the conduit I89. The exhaust line H3 is connected to the pipe I85 leading from the relief valve I83 to the tank 95. A manual control valve I28 is provided in the conduit I I3. The foregoing control system, serves one of the pair of hoisting units A and B shown in Fig. l. The other unit is served by an identical control system, the parts' of which are designated by corresponding numer als, and which is supplied with fluid pressure by the pump 99.

The conduits 88 and I I I which may for the purpose of illustration be understood to serve the unit A, comprise heavy duty flexible hose such as is employed in connection with hydraulic mechanism. These flexible hoses are accommodated in the channels of the rails I I andmay be disposed adjacent the webs I2 of these rails between such webs and the wheels which project thereinto;

The flexible hoses which serve the unit B are designated by the numerals 88 and III and they are disposed in the channel of the other rail II.

The foregoing flexible hoses may be distributed between the channels of the rails II as desired.

In operation of the hydraulic hoisting apparatus the operator first starts the motor 98 by operation of a switch I I4 in the circuit of the motor not shown. Presuming that a vehicle such as shown in Fig. 1 has been driven into proper position over the hoisting apparatus while it is in its contracted state, the operator then opens either valve II8 of the unit A control system or valve I I8 of the unit B control system individually or simultaneously. Fluid pressure is then supplied to the cylinders 58 of the boom rotating mechanism and the boom member is thus rotated to its upright position shown in Fig. 1. The valves II8 are then closed. If it is desired to elevate the vehicle further the valves II2 of the control systems of units A and B are either individually or simultaneously opened thereby admitting fluid pressure to the flexible hoses I I I and III which supply fluid under pressure to the cylinders 25 of the boom member 28. The admission of fluid pressure to the cylinders 25 causes outward extension of the piston members 28 of the boom of each unit A and B thus further elevating the vehicle beyond the level to which it had previously been raised by rotation of the boom members 24.

After the vehicle has been raised to a desired height, all of the manual control valves H8, H2 and I28 are in their closed positions. In order to lower the vehicle the valves I28 are opened and fluid medium is then exhausted from the cylinder 25 of the boom members 24 through the conduit H3 and into the tank 95. Exhausting of fluid from the cylinders 25 is controlled by the differential valve 8| to predetermine the rate of downward movement of the vehicle. When the pistons 28 of the boom structure have been com- 9 pletely retracted the boommembers maybe permitted to rotate toward their horizontal positions by openingof the manual control valves .Hfland H.2to accommodate exhausting of fluid from the cylinder :56 through the flexible con- .duits B8 and 88,-and the conduits I09, valves H2 conduits l l3 into the tank 95. It should be understood that in .order to accommodate rotation of the boom members to their lower positions the valves H aswell as the valves I [2 have to be opened. The requirement of opening two sets of valves in order to rotate the boom members downwardly safeguards the apparatus against unintended downward rotation of the boom members while the piston and cylinder units thereof are extended for opening of the set of valves marked H0 alone or the set of valves marked H2 alone'vvillwnot permit exhausting of fluid from the cylinders "of the boom rotating mechanism. It is believed to be obvious that the ,hoisting units A and B may be operated independently by the foregoing manipulation of only one of each of the sets-of valves 1H], 1 l2, and

=Any fluid-which leaks past the "pistons 51 of the cylinders 56 may now freely back to the tank .85 through a conduit ,l'2l which is connected by branch conduits 12:2 with the rightends of the cylinders -56, as shown in Fig. 2.

The operation of the latches 65 -and60 of each hoisting unit has heretofore been described. Duringthe raisingand the lowering of the boom members the cover plates H are automatically shifted as heretoforeset forth.

Although but one specificembodiment of the invention is herein shown and (described, it will ber, a longitudinally extensible boom :member pivotally mounted "at one end portion on said 'base member for rotative movement in a substantially 'vertical plane between substantially horizontal and uprightpositions and including laterally spacedrigidly connected extensible elements, a load receiving seat on the free end of said boom member, mechanism operable while said extensible elements are in contracted positions for rotating said boom member from its lower toits upright position including means re ceivable in nested relation between said extensible elements of said boom member in its lower position, and means for extending said elements while they are in their upright positions.

2. Hoisting apparatus comprising a base mem her, a boom member comprising laterally spaced piston and cylinder assembliespivotally mounted on said base member for rotative movement in contracted relation for initially lifting an article to a predetermined elevation, article support means mounted on the pistons of said assemblies, means rigidly connecting together the cylinders of said assemblies, means for drivingly rotating said boom member while its piston and cylinder assemblies are in contracted positions to initially elevate a load to said first mentioned elevation and means for supplying, fluid pressure to said cylinders for extending said pistons to lift said article to a higher elevation.

3. Hoisting apparatus comprising a carriage including axle means and wheels journaled thereon, a boom member comprising laterally spaced piston and cylinder assemblies, means extending transversely of said assemblies rigidly connecting the cylinders of said assemblies, means on one end of each of said cylinders pivotally supporting said boom member on said axle means, an article support means mounted on the pistons of said. assemblies, mechanism for rotating said boom member from a substantially horizontal position .to a substantially vertical position about the axis of saidaxle-while its piston and cylinder assemblies arezin contracted positions to initially dift an article disposed on said support to a predeterminedelevation, and means for supplying fluid pressure to saidcylinders to extend said pistons and :said article-to a :higher elevation.

4. Hoisting apparatus comprising abasemember, a boonmmember pivotally .mounted at one end portion on-said base member :for rotative movement in .a substantially vertical plane i and including rigidly connected spaced longitudinal elements, .a load neceiving-seat-on the free end 01' said boom member, and mechanism for rotating said boom member :from its lower to an upright position including. a pair of piston and cylinder assemblies having piston rod portions extending in onedirection from the pivoted end of said boom member and receivablein-nested relation between said longitudinal elements of said boom member .initslo-wer posi-tionnand having cylindenportions extending in an :opposite direction-from said pivoted end of saidboom member, said piston and cylinder portionsbeingrelatively extended when said boommember is in its lower position.

5. Hoisting apparatus comprising a base member, a longitudinally extensible boom -member pivotedon-said base member for rotative movement: in a substantially vertical planeand including laterallyspaced piston and cylinder assemblies,=a load receiving seat on the free end of said boom member, toggle means-pivotally attached atone end to said-boom member, the other end of said .togglemeans being shiftable toward thepivoted end of said boom member for rotating .it fr-Qmits lower to:its upright position, and driving mechanism for said toggle means including a shiftable rod connected with the shiftable end of said toggle means and receivable betweenthe piston and cylinder assemblies of said boommember in its dower position.

.6. Hoisting apparatus comprising a "track including spaced-rail members, a base member on said rail members, an extensible boom member "pivotally mounted at one-end :onsaid base member for pivotalmovement in asubstantiallyverti- .calplane and including a pair of laterallyispaced rigidly connected piston and cylinder assemblies, aload receiving seat on the free end of vsaidboom member carried by the piston portions of said assemblies, toggle means pivotally attached at one end to said boom member and having anop- .posite endshiftable toward the pivoted end of said boom member for rotating it to its upright eluding spaced rails pa base member on said rails,

' a longitudinally extensible boom member pivoted on said base member forrotative movement in.

' a ,substantially vertical plane and including laterally spaced'piston and cylinder assemblies, a load receiving seat on the free end of said boom member, mechanism for rotating said boom member 7 'including toggle means pivotally attached at one end to said boom member, the other end of said toggle means being shiftable toward the pivoted endoif said boom member for rotating it from its lower to its upright position, and a cover plate shiftable relative to said rails and connected with said mechanismior covering and uncovering the V eluding spaced rail members, a base member on said rail members, a boom member pivotally mounted at one end portion on said base member for rotative movement from a substantially horizontal position between said rail members to a substantially upright position, a load receiving seat on the free end of said boom member, mechanism for rotating said boom member from its horizontal to its upright position, and a cover plate shiftable relativeto said rails and connected with said mechanism and shiftable thereby relative to said pivoted end of said boom member for covering and uncovering the space between said rail members as said boom member is rotated from and toward its horizontal position respectively. g g

V 9(Hoisting apparatus comprising a track including spaced rail members, and a base member on said grail members, a boom member pivotally mounted atone end portion on said base member for rotative movement from a substantially horizontal position between said rail members to a substantially upright position, a load receiving seat on the free end of said boom member, toggle links each pivoted at one end on said boom member having opposite end portions shiftable toward the pivoted end of said boom member for rotating it to its upright position, a carriage member comprising spaced wheels engaged with said rail members and shiftable longitudinally of said track, the free end portions of said toggle links being pivotally attached to said carriage, actuating apparatus for shifting said carriage toward the pivoted end of said boom member to rotate it toward its upright position, and a cover plate located on the side of said carriage remote from. the pivoted end of said boom member having one end supported by said carriage and movable therewith relative to said boom member to unboom member having laterally extending portions overlying said rail members and adapted to cover and uncover the space between said rail members occupied by the main portion of said boom member as it is rotated toward and from its substantially horizontal position respectively, a load receiving seat element mounted on the pistons of said assemblies, mechanism for rotating said boom member from its substantially horizontal to its upright position to elevate said seat element and a load thereon to an initial predetermined elevation, and means for supplying fluid pressure to said cylinders for lifting said seat element and said load to a higher elevation.

11. Hoisting apparatus comprising a track including spaced rail members, a base member on said rail members, a boom member pivotally mounted at one end portion on said base member for rotative movement from a substantially horizontal to an upright position, said boom member comprising a pair of laterally spaced piston and cylinder assemblies receivable between said rail members and a plate rigidly secured to the cylinders of said assemblies for rigidifying said boom member and adapted to cover the space between said rail members occupied by the main portion of said boom member when it is in its substantially horizontal position, a load receiving seat element mounted on the pistons of said assemblies, mechanism for rotating said boom member from its substantially horizontal to its upright position to elevate said seat element and a load thereon to an initial predetermined elevation, comprising a second pair of piston and cylinder assemblies disposed between said rail members and comprising toggle linkage means connected with the pistons of the cylinders of said second piston and cylinder assemblies and coacting between the cylinders of said boom member and said rail members, and means for selectively supplying fluid pressure to the cylinders of said first and second piston and cylinder assemblies respectively.

12. Hoisting apparatus comprising a base support, a boom member pivotally mounted at one end portion on said base support for rotative movement from a substantially horizontal to a substantially upright position, a load supporting seat on the free end portion of said boom member, means for rotating said boom member from its horizontal to its upright position, and latch mechanism including a pivotally mounted latch element located adjacent the pivoted end of said boom member and a latch pin on said means automatically engageable with said latch element during the last increment of movement of said boom member toward its upright position for holding-said boom member against unintended movement toward its horizontal position.

13. Hoisting apparatus comprising a base support, a boom member pivotally mounted at one end portion on said base support comprising a piston element and cylinder element assembly, a load receiving seat on the outer end of the piston of said assembly, mechanism for rotating said boom member from a substantially horizontal to an upright position for elevating a load on said seat to a predetermined elevation, means for supplying fluid medium to the cylinder element of said assembly for further elevating said load, and latch mechanism for holding said piston element against outward movement relative to said cylinder element under the action of said fluid pressure when said boom member is in its horizontal position, said latch mechanism including a latch pin on one of said elements and a pivoted latch hook on the other element movable by gravity action into and out of engagement with said latch pin as said boom member approaches its horizontal and upright positions respectively.

14. A vehicle hoist including spaced channel rails having their Webs in vertical planes and having their channel sides facing each other; a carriage shiftably mounted on said rails includinga pair of wheels, each having a peripheral portion engaged in substantially less than the entire depth of the channel of one'rail respectively and each having a flange portion engageable with edges of said ra-il's-fbr limiting inward movements of'saidwheelswith respect to the channels of said rails, a boom member pivotally mounted on said carriage for rotative movement in a substantially verticalplane from a substantially horizontal to a substantially upright position, a seat'member mounted on'thefree end of said boom member adapted to receive a portion of a vehicle, mechanism for rotating said boom member to elevate a portion of said vehicle comprising a piston and cylinder assembly disposed between said rails, a source of fluid pressure, and conduits for supplying fluid pressure from said source to the cylinder of said assembly, portions of said conduits being disposed in a channel of one of said rails between the web of the latter and the'portion of said channel occupied by a wheel of said carriage.

15. A vehicle hoist including spaced channel rails having their webs in vertical planes and having their channel sides facing each other, a carriage shiftably mounted on said rails including a pair of wheels, each having. a peripheral portion engaged in substantially less than the entire depth of the channel. of one rail respectively and each having a flange portion engageable with edges of said rails for limiting inward movements of said wheels with respect to the channels of said rails, a longitudinally extensible boom member pivotally mounted on said carriage for rotative movement inasubstantially vertical plane from a substantially horizontal to a substantially upright position and including piston and cylinder elements, a seat member pivotally mounted on said piston element adapted to receive a por tion of a vehicle, mechanism for rotating said boom member to elevate a portion of a vehicle comprising a piston and cylinder assembly disposed between said rails, a source of fluid pressure, and means including conduits for supplying fluid pressure from said source to the cylinders of said boom member and boom member rotating mechanism, portions of said conduits being disposed in the channels of said rails between the webs of the latter and the portions of said channels occupied by said wheels.

'16. Hoisting apparatus comprising a track including spaced rail members having horizontally extending flanges, and base members on said rail members, a boom member pivotally mounted at one end portion on said base member for rotative movement from a substantially horizontal position between said rail members to a substantially upright position, a load receiving seat on the free end of said boom member, mechanism for rotating said boom member from its horizontal to its upright position including a toggle link having one end pivoted on said boom member and its other end shiftably connected with one of said rail members and including apparatus for shifting the latter end of said link toward the pivoted end of said boom, and a stop on said link engageable with one of said rails for limiting rotation of said boom to a position sufiiciently off vertical to facilitate return rotation of said boom toward its horizontal position under the action of its weight.

17. Hoisting apparatus including a track comprising spaced rails, a carriage having wheels mounted om said rails, alongitudinally extensible boom. member pivotally mounted on, said carriage for rotation in: arverti'cal plane between av substantially. horizontal position between said rails and a substantially upright position and including a pair of. laterally spaced piston and cylinder assemblies, a load" receiving seat pivotally mounted'lon the outer ends of the pistons of said assemblies, a pair of toggle links. one pivotally mounted on each side of said boom member. a wheelrand axle assembly pivotally connected with the free ends of said toggle links, the wheels of said assembly being shiftably engaged with said rails and held thereby against vertical movement, and mechanism for shifting said wheel and axle assembly toward the pivoted end of said boom member to rotate the latter to its upright position, said wheel and axleassembly being spaced from said boom member in its horizontal position 191' accommodating nesting of portions of said load receiving seat therebetween and between said rails.

18. Vehicle hoisting apparatus including spaced tracks, a pair of hoisting units. one shiftably and the other non-shiftably mounted on said tracks each including a base structure, a boom member pivotally mounted adjacent one of its ends on each of said base structures, mechanism for rotating the boom member of each unit from a relatively horizontal to a relatively upright position, and a seat element pivotallymounted on the free end of each of said boom members, one seat element being adapted to receive a part of a front end portion of a vehicle and the other seat element being adapted toreceive a part of therear end portion ofsaid vehicle, said seat elements being free from connection to eachother except through said vehicle andbeing held by'engagement with said vehicle parts in a substantially horizontal load supporting relation during rotation of saidboom members.

19. Vehicle hoisting apparatus including spaced tracks, a pair of hoisting units one shiftably and the other non-shiftably mounted on said tracks each including a base structure, a boom member comprising a rigid arm like structure pivotally mounted adjacent one of its ends on each of said base structures, mechanism for rotating the boom member of each unit from a relatively horizontal to a relatively upright position, a seat element pivotally mounted on the free end of each of said boom members, one seat element being adapted to receive a part of a front end portion of a vehicle and the other seat element being adapted to receive a part of a rear end portion of a vehicle, said seat elements being free from connection with each other except through said vehicle and being held by engagement with said vehicle parts in a substantially horizontal load supporting relation during rotation of said boom members, and abutment members on said boom members and seats respectively engageable when said boom members are in their upright positions for positively limiting relative pivotal movements of said seats and boom members.

20. Vehicle hoisting apparatus including spaced tracks, a pair of hoisting units one shiftably and the other non-shiftably mounted on said tracks each including a base structure, a boom member comprising a rigid arm like structure pivotally mounted adjacent one of its ends on each of said base structures, mechanism for rotating the boom member of each unit from a relatively horizontal position to a relatively upright position, a seat element pivotally mounted on the free end. of each of said boom members, one seat element being adapted to receive apart of a front end portion of a vehicle and the other seat element being adapted to receive a part of a rear end portion of a vehicle, said seat elements being held by engagement with said vehicle parts in a substantially horizontal load supporting relation during rotation of said boom members, and means coacting frictionally between the said boom member of each unit and its associated seat for holding the latter against unintended pivotal movement when disengaged from a vehicle.

21. Hoisting apparatus comprising a track including spaced rails, a base member on said rails,

a boom member pivoted on said base member for rotative movement in a substantially vertical plane, a load receiving seat on said boom member, mechanism for rotating said boom member including toggle means pivotally connected at one end to said boom member, the opposite end of said toggle means .and the pivoted end of said boom member being relatively shiftable toward each other for rotating said boom member from its lower to its upper position, and a cover plate shiftable relative to said rails and connected with said mechanism for covering and uncovering the space between said rails as said boom member is rotated by said mechanism from and toward its lower position respectively.

22. Hoisting apparatus comprising a track including spaced rails, a base member on said rails, a boom member pivotally mounted at one end portion on said base member for rotative movement from a substantially horizontal position between said rails to a substantially upright position, a load receiving seat on said boom member. mechanism for rotating said boom member from its horizontal to its upright position, a cover plate shiftable relative to said rails and'connected with said mechanism for covering and uncovering the space between said rails as said boom member is rotated by said mechanism from and toward its horizontal position respectively, and a cover plate carried by said boom member adapted to cover and uncover said space between said rails as said boom member is rotated toward and from its horizontal position respectively.

23. Hoisting apparatus including a track comprising spaced rails, a carriage having wheels mounted on said rails, a boom member pivotally mounted on said carriage for rotation between a substantially horizontal position between said rails and an upper position, a load receiving seat pivotally mounted on the outer end portion of said boom member, mechanism for rotating said boom member including toggle links pivotally connected with said boom member at one end and a wheel and axle assembly pivotally connected with the opposite-ends of said toggle links and shiftably engaged-with said rails, and mechanism for relatively shifting said assembly and said carriage to rotate said boom member toward its upper position, said wheel 'axle assembly being spaced'from said boom member in its horizontal position for accommodating nesting of portions of said load receiving seat therebetween and between said rails.

- i 7 DAVID A. WALLACE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,015,357 Weaver Sept. 24, 1935 2,182,676 Nilson Dec. 5, 1939 2,326,594 Wood Aug. 10, 1943 FOREIGN PATENTS Number Country Date 297,907, Italy June 23, 1932 342,093 Great Britain Jan. 29, 1931 530,526, Great Britain Dec. 13, 1940 

